Extra-sensory perception, or ESP, refers to the supposed ability to
acquire information by some means other than the normal human senses, such as
the traditional five senses of taste, sight, touch, smell, and hearing, or any
of the other senses well known to science (balance, proprioception, etc.)

Because the definition of sense is vague, the the precise definition of
extra-sensory is as well, but the term is generally meant to imply sources
of information unknown to modern science. Despite the vagueness of the definition, no one has ever demonstrated ESP in a generally accepted way. The James Randi Educational Foundation (http://www.randi.org/) offers $1 million to anyone who can demonstrate ESP or any psychic phenomenon. No one has ever collected.